Timber Construction Calculator

Span tables, insulation R/U-value, material quantity, plus rafter, stairs, and footings — based on KS standards and Korean building code.

Structural · Insulation · Quantity (Core)

Maximum allowable span for joists, rafters, and headers via bending + deflection check.

Multi-layer wall composite R-value and U-value with auto pass/fail per Korean energy code.

Sheets of OSB, plywood, gypsum, siding from area and waste factor + nail/screw estimate.

Compute number of steps, riser height, and tread depth per Korean building code.

Compute rafter cut length, angle, and slope from run and rise.

Convert between angle, slope (%), and pitch (rise/12) representations.

Plan area + slope angle → actual roof slope area + eave area.

Strip footing or mat slab concrete volume + rebar weight + remicon truck count.

Convert lumber dimensions and count into volume, board feet, sai, and weight.